"a new danger" is correct and usable in written English.
You could use it in a sentence such as, "The rise of artificial intelligence presents a new danger to humanity."
There then follows a new danger.
But when darkness falls, the villagers face a new danger.
But a new danger has arisen for newspapers.
Behind yesterday's latest round in the elite musical chairs lies a new danger.
They want to attend to crops and livestock and guard their houses against looters, despite a new danger of mudflows.
While the various Balkan states fought among themselves for domination in the area, a new danger appeared in the south.
Mr. Khashoggi understood that challenging the brash 33-year-old prince posed a qualitatively new danger for internal critics, that M.B.S. demanded a monopoly on the narrative of his reforms and would let no one challenge it.
Instead, Mr. Greenspan's case for a tax cut rests entirely on his perception of a curious new danger -- the peril of zero debt.
The attack exposed a stark new danger for foreign diplomatic workers in Iraq, and contributed to the United Nations' decision to scale back its presence sharply as violence deepened.
In turn, the Shiites have been cautiously more supportive of American efforts here, and Mr. Sadr's followers appear to represent a possible new danger to the American troops.
Experience in Asia shows that as broadband spreads and computers are connected 24 hours a day, new dangers emerge: data miners, hackers, "Trojan horses" and potentially most dangerous of all network viruses.
